Playground Safety Zones and Fall Height: How They Are Determined

Anyone reviewing or drawing up a playground layout eventually runs into the same question: how much space needs to be left around a given piece of equipment, and what has to happen to the ground within that space. The answer is not a single number that applies across an entire site. It is the result of a process that starts with the equipment itself, its design, height and how the user moves on or around it, and only then arrives at a zone dimension and a surfacing specification.

For an architect coordinating a concept design, or a technical planner reviewing a public sector client's documentation, this matters because fall zones directly affect everything else on the plan: paths, benches, fencing, drainage, planting and the spacing between individual pieces of equipment. Getting the zone concept right early avoids having to redraw the layout later, once equipment has already been chosen and the plan drawn to a scale that assumed the wrong clearances. This article explains how HRN EN 1176-1:2023 determines the space around equipment and free fall height, where EN 1176 and EN 1177 each apply, and what to check on a layout before treating it as final. It builds directly on our articles explaining what EN 1176 actually is and the difference between the equipment standard and the surfacing standard, and it assumes familiarity with both.

The standard does not use the term "safety zone" as such. What is commonly called that is defined in HRN EN 1176-1 as minimum space, the space needed for the safe use of equipment, made up of three parts.

The first is the space occupied by the equipment itself. The second is free space, the space in, on or around the equipment occupied by the user while going through the movement the equipment imposes, for example sliding down a slide, swinging or rocking. The third is fall space, the space through which a user may pass when falling from an elevated part of the equipment. The ground a user could hit in such a fall is what the standard calls the impact area, and it is this area that impact attenuating surfacing requirements relate to.

This distinction is not a technicality. Free space and fall space have different rules on overlapping with neighbouring equipment and different rules on what may be located within them, so a layout that treats them as a single zone cannot correctly satisfy both requirements.

Free fall height is a property of the equipment. The standard defines it as the greatest vertical distance between a clearly intended body support and the impact area beneath it, capped at a maximum of 3,000 mm. How it is measured depends on how the equipment is used: from the foot support when standing, from the seat when sitting, from the hand grip height when hanging, and from the highest hand grip when climbing, measured in full with no arm's-length deduction — and the resulting free height of fall may not exceed 3,000 mm. The determination takes into account the greatest possible movement of the equipment and user, and roofs or other parts not intended for play are excluded from the calculation if access to them is not encouraged.

Critical fall height is a property of the surfacing, not the equipment. It is the maximum free fall height for which the surfacing provides an adequate level of impact attenuation, established by testing under EN 1177. The compliance rule linking the two is: the critical fall height of the surfacing must be equal to or greater than the free fall height of the equipment above it. Confusing these two terms is one of the most common sources of error in project documentation, because the same expression then gets used for both an equipment requirement and a surfacing property, making it easy to miss that these are two sides of the same check.

The sequence always runs in one direction: the equipment's design determines its free fall height, and free fall height determines both the required dimensions of the fall space and impact area and the surfacing performance needed within that area. Space is never allocated independently of the equipment sitting within it. That is why two apparently similar structures can require different amounts of space, and why a zone drawn for one piece of equipment cannot simply be reused for another, even a similar one, without checking its specific free fall height.

Fall space and free space are functional requirements, not marked lines on a drawing. The standard explicitly requires that the fall space be free of obstacles a user could fall onto and be injured by, such as posts not flush with surrounding surfaces or protruding footings. Only load-bearing or supporting parts, neighbouring structural parts whose free fall height differs by less than 600 mm, and parts inclined at 60 degrees or more from horizontal are permitted, since a user falling onto these would only graze them. Free space must not contain anything that obstructs a user's imposed movement, such as branches, ropes or crossbeams, and the playground's main pedestrian routes must not pass through it. A zone that is correctly dimensioned on paper but has a bench standing inside it, or a path running through it, does not meet the intent of the requirement even if the drawn boundary looks correct. This is one of the most common gaps between a drawing that looks compliant and a playground that is actually built to comply, and it is worth checking deliberately rather than assuming a correctly dimensioned zone automatically means a correctly clear zone.

Free fall height is the starting variable, and HRN EN 1176-1 sets out general rules that apply to all equipment, while the individual parts of the standard covering swings, slides, cableways, roundabouts and rockers adapt those general rules for each equipment type.

General rules for fall space and impact area

Fall space extends at least 1,500 mm around elevated parts of equipment, measured horizontally from the vertical projection of the equipment. For free fall heights up to 1.5 m, the impact area extends 1.5 m from the equipment. Above 1.5 m, the extension increases according to the formula X = 2/3 of fall height + 0.5 m, so equipment with a free fall height of 3 m, for example, requires an impact area extending 2.5 m. In particular cases, such as a roundabout that gives the user horizontal velocity, the impact area is extended further.

Free space for equipment with imposed movement

Free space is defined as a series of cylindrical spaces representing the user along the path of imposed movement. For a standing user the cylinder has a radius of 1,000 mm and a height of 1,800 mm, for a seated user a radius of 1,000 mm and a height of 1,500 mm, and for a hanging user a radius of 500 mm with 300 mm above and 1,800 mm below the grip position. That is why the shape of the zone on a plan for swings and slides differs from the zone around a climbing frame even when the equipment reaches a comparable height: for a swing, the space follows the arc of movement and the point at which a user might leave the seat, and for a slide, the exit path at the end of the chute, following the rules in the relevant equipment-specific parts of the standard.

Overlap rules

Fall spaces, including impact areas, may in most cases overlap. Overlap is not permitted where imposed movement is involved, and where two pieces of equipment with different fall heights sit together, the larger of the two impact areas governs. For free space, the rule is stricter: the free spaces of neighbouring equipment must not overlap with each other, and the free space of one piece of equipment must not overlap with the fall space of another, with an exception for shared space within combined units.

Why the same type of equipment can require a different zone depending on height and design

"The same type of equipment" is not the same as "the same space requirement." A slide that is taller than another, or has a steeper chute, a different exit angle or a different platform height, has a different free fall height, and therefore a different required space, even if both are described as "a slide" in the specification. The same logic applies to climbing frames, combined units and freestanding play elements. The size of the space follows the specific piece of equipment as designed and tested, not a generic category label. This is one reason equipment selection and layout planning should be aligned with the actual manufacturer's documentation for the specific product, not a general assumption based on equipment type.

These two standards work together but regulate different things, and confusing their scope is a common source of errors when reviewing a layout. A more detailed comparison is covered in our article on equipment versus surfacing under EN 1176 and EN 1177; the summary relevant here is narrower.

EN 1176: equipment, spaces and surfacing thresholds

EN 1176 is the standard covering the playground equipment itself, including design, manufacturing and installation requirements. It defines free fall height, fall space, free space and impact area, as well as the thresholds at which impact attenuating surfacing is mandatory: beneath all equipment with a free fall height greater than 600 mm, and beneath equipment that imposes movement on the user, such as swings, slides, rockers and roundabouts, where the entire impact area must be covered with impact attenuating surfacing. For equipment with a fall height up to 600 mm and no imposed movement, surfacing testing is not required. The standard also lists common materials accepted without further testing in a materials table: well-maintained grass for fall heights up to 1,000 mm, and bark, wood chip, sand and gravel of specified particle size at a depth of 200 mm for heights up to 2,000 mm, or 300 mm for heights up to 3,000 mm, with an additional 100 mm of depth required for loose-fill materials to allow for displacement during use.

EN 1177: surfacing performance and HIC (Head Injury Criterion)

EN 1177 regulates impact attenuating surfacing: how it is tested and how its performance is expressed, including through the Head Injury Criterion (HIC), a measure used to assess how well the surfacing reduces the severity of an impact to the head. The result of this testing is the surfacing's critical fall height. EN 1177 does not define space clearances. It defines what the surfacing needs to be capable of achieving for a given fall height, once the space dimension has already been established under EN 1176. In practical terms: EN 1176 states how large the space needs to be, where it sits, and when surfacing is mandatory; EN 1177 states whether the surfacing within that space is adequate, meaning whether its critical fall height is equal to or greater than the equipment's free fall height.

Translating fall height and space requirements into a finished layout drawing and specification is best treated as a defined sequence of steps, not a single check carried out once at the end. This section is accompanied by a diagram illustrating that process; the sequence itself is described here in general terms, since exact figures always depend on the specific equipment being specified.

This sequence is also where a layout review is most useful before the specification is finalised, since adjustments on a drawing are far easier to make than after equipment has already been ordered or installed.

A handful of misconceptions recur consistently when reviewing layout drawings, and they are worth naming directly.

The figures given in this article are the general rules from Part 1 of the standard, HRN EN 1176-1:2023, and apply wherever the equipment-specific parts of the standard do not specify otherwise. The equipment-specific parts, covering swings, slides, cableways, roundabouts, rockers and spatial network structures, adapt these general rules, sometimes by increasing space due to imposed movement, sometimes through a different measurement method. In addition, the free fall height of a specific product depends on its design and is established in the manufacturer's documentation.

For that reason, exact clearance figures should always be confirmed against two sources together: the relevant part of EN 1176 for that equipment category, and the manufacturer's own technical documentation for the specific product being specified. A layout drawn without that confirmation carries a risk that only becomes visible once the equipment has been ordered, or worse, once it has been installed.

This checklist works well alongside our broader overview of the layout planning sequence in how to plan a playground, and the documentation expectations described in what public sector clients should prepare. For a wider look at where fall zone mistakes tend to surface late in a project, see common playground safety mistakes to catch before opening.

REDOX treats the spaces around equipment and the surfacing beneath it as part of one continuous design decision, not an afterthought, since the size of the space follows directly from the equipment chosen and its free fall height. Separating the two, choosing the equipment first and working out the zones later, is precisely how layouts end up needing rework once it becomes clear the clearances do not fit.

As a manufacturer that also designs and prepares its own equipment, REDOX can indicate free fall height and the required clearances early in the layout planning process, before the specification is finalised. That means an architect working on a concept design can understand how a given piece of equipment's space affects the rest of the site while there is still room to adjust the layout, rather than discovering a conflict only after the equipment has already been ordered.

Architects working on a layout can send their equipment selection and site dimensions for a review of how the fall zones fit the available space. This is process and documentation support intended to help move a layout towards a workable specification, not a guarantee of compliance or a certification of the finished site.

Request a fall zone review for your layout drawing. Architects reviewing or preparing a concept design can ask REDOX to check whether the proposed equipment and clearances fit correct fall zones before the specification is finalised.